Hassan Hayat TheSeamau5

Communicating Sequential Processes (CSP)

CSP is one of the many ways of reasoning about concurrent systems. It emphasizes on the idea of a channel which enables communication between producers and consumers and where the channel itself is fundamentally decouple from either producers or consumers.

Queues

The easiest way of thinking about a channel is to think about a queue. A queue is very simple, it is a data structure where one may only push data to the end of a queue and may only read data from the front of the queue.

In pseudo-code:

Record Example

The following is an example of how to:

create a nested record type
encode this as JSON
decode a JSON string to an entity
create a random Entity generator
test the JSON parsing of the Entity

Macros/Metaprogramming in Programming Languages

The following is a list of programming languages and their syntax for doing metaprogramming.

C

Macros in C are just glorified string substitution.

	type alias Bounds = {
	left : Float,
	right : Float,
	top : Float,
	bottom : Float
	}

	bounds : Bounds
	bounds = Bounds 0 0 0 0

	import Svg (Svg, circle, svg, g, line, text)
	import Svg.Attributes (cx, cy, r, fill, stroke, strokeWidth, x, y, x1, x2, y1, y2, fontSize, style)
	import Html
	import Html.Attributes as Html

	import Signal (Signal, map, foldp)
	import DragAndDrop (mouseEvents, MouseEvent(..))
	import List

	--------------

	import Graphics.Collage (..)
	import Graphics.Element (..)
	import Graphics.Input (..)
	import Color (..)
	import Signal (..)

	import Text
	import List
	import Mouse

	{-
	This is an example of how to test state in Elm.
	The idea is that one can model your application as a state machine
	with an update function of the type:

	update : action -> state -> state

	This is very useful in order to test applications
	built using the Elm architecture, which looks like this:

	--------------------------
	-- CORE LIBRARY IMPORTS --
	--------------------------
	import Task exposing (Task, succeed, andThen, onError)
	import Json.Decode exposing (Decoder, object2, (:=), string, int, list, map)
	import Signal exposing (Signal, Mailbox, mailbox, send)
	import List

	---------------------------------
	-- THIRD PARTY LIBRARY IMPORTS --

	/**
	* Sample React Native App
	* https://github.com/facebook/react-native
	*/
	'use strict';

	var React = require("react-native");

	var {
	AppRegistry,

	shrinkInt : Int -> List Int
	shrinkInt n =
	if n < 0
	then
	-n :: List.map ((*) -1) (series 0 -n)
	else
	series 0 n


	series : Int -> Int -> List Int